1. Field of the Invention
The present invention relates to a composition and methods for production and use of industrial chemicals extracted from biomass, and more specifically, to a tobacco extract for corrosion inhibition treatment of metallic surfaces.
2. Description of the Prior Art
Corrosion is defined as the loss of the essential metallic properties of a metal. Corrosion consumes increasingly scarce raw materials and wastes the energy expended in the extraction and refining of metals as well as that involved in manufacturing components and structures. Since corrosion affects virtually every aspect of modern civilization, corrosion prevention is of major economic and environmental importance.
One approach to corrosion control is to add an inhibitor to the system. One way an inhibitor works is that it reacts with the metal to form a protective surface film. Typical examples are the inhibitors added to automobile cooling systems and corrosion-inhibiting pigments in protective paints for metals. However, many corrosion inhibitors in current use are toxic and/or have an adverse effect on the environment. There is increasing legislative pressure for the elimination of heavy metal compounds and toxic organic and inorganic corrosion inhibitors such that the development of effective and environmentally-friendly inhibitors is of major importance.
There have been few advances in the development of novel and effective corrosion inhibitors in recent years, while at the same time, there is a legislation-driven trend to eliminate many of the inhibitors in common use. Thus, inhibitors based on heavy metals, e.g., lead compounds, chromates, and those containing a variety of toxic anions, e.g., nitrites, phosphates and benzoates, are no longer acceptable. Consequently, a high proportion of corrosion inhibitors currently used in chemical industry, paint technology, metal finishing, cooling systems, and so forth require replacement by environmentally-acceptable substances. There is, however, little information on environmentally-acceptable corrosion inhibitors.
Tobacco products contain high concentrations of alkaloids, fatty acids and N-containing compounds, many of which inhibit metallic corrosion. Compounds leached from tobacco with water have the ability to inhibit metallic corrosion. In particular, tobacco extracts inhibit the galvanic corrosion of steel when coupled to copper in a sodium chloride solution, a solution known to rapidly corrode iron and steel. In fact, tobacco extracts appear to be more effective in inhibiting corrosion than the well known inhibitor, potassium chromate, under the same conditions.
There are numerous advantages of using tobacco extract as a metallic corrosion inhibitor. Initially, tobacco is a natural, renewable, environmentally benign, and relatively inexpensive source. In addition to leaves, tobacco waste (stems, twigs, etc.) can be used for corrosion inhibitor extraction. The active constituents (metallic corrosion inhibitors) in tobacco can be readily, inexpensively, and commercially extracted in a simple operation using only water as an extraction medium. In addition, the corrosion inhibitors in tobacco constituents can be extracted in a variety of additional or alternative media, as in steam, organic solvents, acids, etc. Treating metals and metallic surfaces with the extracted corrosion inhibitors can be effected by a number of currently used commercial methods, as in by dip or spray coating, electrostatic coating, or by formulating the corrosion inhibitors with paint or other coatings to be applied to the metallic surfaces in conventional commercial methods.